This invention relates to a sputtering target for forming thin films by sputtering and more particularly to a sputtering target which an be applied to a long-term use for the thin films formation, that is, can be used repetitiously for the formation of many thin films and which can afford to form thin films of high purity at high rates.
As disclosed in Japanese Patent Unexamined Publication No. 59-89413, a sputtering target used for a conventional method for forming composite films has a structure wherein a silicon disc, a molybdenum ring and a doughnut-like silicon ring are arranged concentrically. Consequently, it has been considered that the conventional method permits forming a film pattern of refractory (high melting point) metal silicide which can be used as a considerably low-resistance wiring pattern for gates for achieving a high speed integrated circuit. In connection with this method for forming an integrated circuit pattern, Japanese Patent Unexamined Publication No. 59-133369 (Japanese Patent Application No. 58-7261) discloses a method of mounting the sputtering target.
No consideration was made in this method, however, about the controlable area or rate of the sputtering target surface nor on the lifetime of the target for producing alloy films of controlled composition.
Meanwhile, Japanese Patent Unexamined Publication No. 58-199860 (Japanese Patent Application No. 57-81457) discloses technique directed to increasing film formation speeds (or growth rate) and obtaining films of high quality and which is considered to be able to control composition in the course of formation of alloy films. This technique, however, took no account of applicability of a sputtering target for high formation rate in the film formation.